WARRENVILLE, Ill. — Navistar, parent company of International Truck and Engine, posted a profit of $234 million for the first quarter of 2009.

The company attributed the profit to its military segment as well as gains in Class 8 market share. It noted the profit was achieved during “the weakest North America truck market in nearly 35 years.”

The company downgraded its outlook for the North American Class 6-8 US and Canadian truck market (including school buses) to between 210,000 and 225,000 units this fiscal year. That’s down from a previous forecast of 244,000-256,000 units.

A year ago, Navistar posted a $65 million loss for the first quarter.

“Building on our successful 2008 performance, we delivered a profitable first quarter due in part to the strength of our diversification strategy, increased market share in the heavy truck segment and our expanding military business,” said Daniel C. Ustian, Navistar chairman, president and chief executive officer. “By leveraging our core strengths and the strengths of companies that have become our partners, we are able to maximize our ability to remain profitable during a third consecutive year of low truck volumes.”

Navistar says it has increased its Class 8 market share by 9% since the same time last year. Engine production was down by 34,900 units in the quarter. Ustian said he anticipates Navistar’s 2010 emissions solution will result in a competitive advantage going forward.

“We anticipate EGR will provide our customers with a simple and straightforward solution that places the burden of emissions compliance on the manufacturer, not the customer,” Ustian said.

“Despite the difficult economic environment we currently are operating in, we have sufficient liquidity and borrowing capacity to execute our strategies,” he added.